A Genetic Mutation. – Kavya Ravela Sickle Cell Anaemia A Genetic Mutation. – Kavya Ravela

What Is Sickle Cell Anaemia? Sickle cell anaemia is the most common form of sickle cell disease (SCD). SCD is a serious disorder in which the body makes sickle-shaped red blood cells. “Sickle-shaped” means that the red blood cells are shaped like a crescent. Normal red blood cells are disc-shaped and look like doughnuts without holes in the centre. They move easily through your blood vessels. Red blood cells contain an iron-rich protein called haemoglobin. This protein carries oxygen from the lungs to the rest of the body.

Sickle cells contain abnormal haemoglobin called sickle haemoglobin or haemoglobin S. Sickle haemoglobin causes the cells to develop a sickle, or crescent, shape. Sickle cells are stiff and sticky. They tend to block blood flow in the blood vessels of the limbs and organs. Blocked blood flow can cause pain, serious infections, and organ damage.

Figure A shows normal red blood cells flowing freely in a blood vessel Figure A shows normal red blood cells flowing freely in a blood vessel. The inset image shows a cross-section of a normal red blood cell with normal haemoglobin.

Figure B shows abnormal, sickled red blood cells blocking blood flow in a blood vessel. The inset image shows a cross-section of a sickle cell with abnormal (sickle) haemoglobin forming abnormal strands.

Over View Sickle cell anaemia is one type of anaemia. Anaemia is a condition in which your blood has a lower than normal number of red blood cells. This condition also can occur if your red blood cells don't contain enough haemoglobin. In sickle cell anaemia, the number of red blood cells is low because sickle cells don't last very long. Sickle cells usually die after only about 10 to 20 days. The bone marrow can't make new red blood cells fast enough to replace the dying ones. Sickle cell anaemia is an inherited, lifelong disease. People who have the disease are born with it. They inherit two genes for sickle haemoglobin—one from each parent.

Genetics Behind Sickle Cell Anaemia The chain of coloured boxes represent the first eight amino acids in the beta chain of haemoglobin. The sixth position in the normal beta chain has glutamic acid, while sickle beta chain has valine. This is the sole difference between the two. Gametic Mutation Gene Mutation Substitution (T is swapped with A)

This Bit is Basically Copy and Paste… Maybe someone can edit it and make it simpler? Haemoglobin consists of four protein subunits, typically, two subunits called alpha-globin and two subunits called beta-globin. The HBB gene provides instructions for making beta-globin. Various versions of beta-globin result from different mutations in the HBB gene. Abnormal versions of beta-globin can distort red blood cells into a sickle shape. The sickle-shaped red blood cells die prematurely, which can lead to anaemia. Sometimes the inflexible, sickle-shaped cells get stuck in small blood vessels and can cause serious medical complications. How do people inherit sickle cell disease? This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Treatment Sickle cell anaemia has no widely available cure. However, treatments can help with the symptoms and complications of the disease. Blood and marrow stem cell transplants may offer a cure for a small number of people. Over the past 100 years, doctors have learned a great deal about sickle cell anaemia. They know its causes, how it affects the body, and how to treat many of its complications.

Treatment Sickle cell anaemia varies from person to person. Some people who have the disease have chronic (long-term) pain or fatigue (tiredness). However, with proper care and treatment, many people who have the disease can have improved quality of life and reasonable health much of the time. Due to improved treatments and care, people who have sickle cell anaemia are now living into their forties or fifties, or longer.